JPS597883A - Irradiation heating furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to an irradiation heating furnace.

Among devices generally used for heat treatment, an irradiation heating furnace that irradiates a workpiece with radiation from a lamp has the following features.

■) Because the heat capacity of the lamp itself is extremely small.

A rapid increase and decrease in heating temperature is possible.

2) By controlling the power supplied to the lamp, the heating temperature can be easily controlled (2).

3) Since it is non-contact heating using radiation light from a lamp,
It does not contaminate the object to be processed.

4) It takes less than 9 hours to start up after starting, and energy efficiency is high, so energy consumption is low.

5) Compared to direct current furnaces, high frequency furnaces, etc., the equipment is smaller and the cost is lower.

The irradiation heating furnace is used for heat treatment and drying of sushi wood, etc.

Used in plastic molding, thermal property testing equipment, etc. Particularly recently, processes that require heating in semiconductor manufacturing, such as impurity diffusion processes, chemical vapor deposition processes, recovery processes for crystal defects in ion implantation layers, heat treatment processes for electrical activation, and The use of an irradiation heating furnace in place of the conventionally used electric furnace, high-frequency furnace, etc. is being considered as a heating furnace when carrying out a heat treatment process for nitriding or oxidizing the surface layer of a silicon wafer. In addition to the fact that irradiation heating furnaces do not contaminate the objects to be treated or have any adverse electrical effects, and consume less power, conventional heating furnaces can evenly process large areas of objects. This is because it cannot be heated to a high temperature and cannot respond to the recent increase in the area of semiconductors.

As mentioned above, irradiation heating furnaces have various features and are widely used in industry, but conventional irradiation heating furnaces do not irradiate and heat the surface of large areas of workpieces at a uniform temperature. There is a drawback that it cannot be done. In other words, the u/p has an envelope made of quartz glass or the like and forms a point light source or a line light source, and cannot form a surface light source with a two-dimensional spread when used alone. Although it is possible to uniformly heat a small area, it is not possible to uniformly heat a large area. In particular, when the object to be processed is, for example, a semiconductor wafer, the temperature at the periphery becomes lower than the temperature at the center due to heat dissipation, resulting in an unexpectedly large temperature difference. Damage called ``slip rhino'' may occur from the lower part to the middle part.

The present invention was made based on the above circumstances, and an object of the present invention is to provide a novel irradiation heating furnace that can heat the surface of a large area of a workpiece at a uniform temperature.
Its characteristic feature is that a plurality of lamps, each consisting of a filament with alternating non-light-emitting parts and light-emitting parts placed inside a long rod-shaped tubular envelope along the tube axis of the envelope, are placed close to the mirror. and the tube axes thereof are parallel to each other, and at least one of the plurality of lamps located on the end side,
The point is that it is displaced so as to approach the level at which the workpiece to be heated by being irradiated with light is positioned.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an irradiation heating furnace according to an embodiment of the present invention. In this embodiment, as also shown in FIG. Main mirrors 2 and 3 are respectively arranged so as to cover the main mirrors. A plurality of semicircular concave grooves m are formed in line on the reflective surface of each of the main mirrors 2 and 3, and are arranged in the lateral direction of the main mirrors 2 and 3 (left and right directions in FIG. 1). In Fig. 2, the grooves extend over their entire length in the direction perpendicular to the plane of the paper, and among these grooves m, grooves Pi m1+m2 and grooves m31m4 are located at both ends of mirror 2 and mirror 3, respectively. teeth,
Other grooves m and p other than these grooves +m2 +m3 +m4 are also provided so as to be displaced so as to approach the level P at which the object to be processed is located in the irradiation space 1. A first air path member 4 is connected to the lateral edges of the main mirrors 2 and 3, and a blower 5 is connected to the first air path member 4. A second air path member 6 is connected to the other side edge in the lateral direction.
An exhaust fan 7 is connected to. One lamp support 8 and the other pipe support 9 are provided near the outlet of the first air path member 4 and near the entrance of the second air path member 60, respectively. and 9, respectively, the main mirror 2
and supporting both ends of the container 10 such as a long bar-shaped halogen lamp so as to extend along 4 fl*m in 3,
Therefore, the lamps 10 are arranged so as to face the irradiation space 1, and the concave @
m1. Lamps 101° 102 and u/p 103.10 arranged opposite m2 and concave fill m3 + m4
4 is these U/P 101.102.103.104
The other plates 10 and 10 are also displaced so as to approach the level P where the object to be processed is located in the irradiation space 1. Furthermore, the upper supporter 8
and 9 are fixed by screws 24 to side mirrors 2o and 21 having mirror surfaces on their inner surfaces, which are arranged so as to cover both sides of the irradiation space l, as shown in FIG. In cooperation with the container receiving grooves 22 formed at positions corresponding to the grooves m on the upper and lower edges of each of the grooves, the container 10 is held in its sealing part by the groove-shaped holding part 23. 12.12, so that each sealing part 12.12 of the lamp lO is held in place as shown in FIG.
is exposed to the outside, that is, inside the first air path member 4 and the second air path member 6, and the external lead 14.14 extending beyond the exposed sealing portion 12.12 has a first Air channel member 4
And the wall of the second air passage member 6 is covered with an insulating material 25 such as Teflon.
．． A current supply line 26.26 is connected which extends through 25. A water cooling mechanism is formed in the main mirrors 2 and 8° and the side mirrors 20 and 21, specifically, a water conduit W passing through the material members of the main mirrors 2 and 3 and the side mirrors 20 and 21. , connect the cooling water supply mechanism to this.

Here, as shown in FIG. 4, the lamp 10 includes a tubular enclosure 11 made of quartz glass, and a metal foil seal sealed in sealing parts 12, 12 at both ends of the enclosure 11. a conductive member 18.18, external leads 14.14 extending from the conductive member 13.13 to the outside of the enclosure 11, and internal leads 15.15 extending from the conductive member 18.18 into the enclosure 11, respectively. , these internal leads 15.
15 and a filament 16 disposed along the tube axis of the envelope 11, and a filament supporter 17. has end non-light emitting parts N', N'. To give a specific numerical example, the main mirror 2
The diameter d1 of the groove m of No. 8 is Zoll, the distance d2 between the centers of the adjacent grooves m is 21mm, the total length kl of the lamp lO is 885m, and the outer diameter of the tubular portion of the enclosure 11 is 10mm.

The length of each of the non-light emitting parts N' and N' at both ends of the filament 16 is 87 dews, and the non-light emitting parts N' at both ends of the filament 16 are
, the length excluding N' is 3, which is 280111. lamp l
The rating of O is 280V-8200W, and the distance Ll between the lamps IO in the center facing each other through the irradiation space l is 80mm. distance L
2 and L3 are respectively 60 fight and 40 - side mirror 20
and 21, the distance L4 between them is 280 m.

For each groove m, the lamp 10 is arranged so that the tube axis is located at a position displaced 1 to 2n toward the bottom from the center of the semicircle associated with the groove m.

The blower and exhaust device connected to the first air passage section numbered part and the second air passage member 6 have a maximum air volume of 8 i/min. Therefore, from the trap of turning on lamp 10, the main mirror]
With the addition of reflections from
(See figure) The irradiation space l is moved by a transfer mechanism such as a belt conveyor so that the object to be treated passes through the irradiation space l through 30°81.
By positioning the object inside, the object to be processed is heated.

According to the above configuration, a plurality of rod-shaped lamps 10 are arranged in parallel in a dense manner so that their tube axes are parallel to each other. For the object to be treated in the space 1, the plurality of lamps 10 effectively form a surface light source, and each lamp 10 has its filament 16 alternately having a non-light-emitting part N and a light-emitting part R. Therefore, the emission intensity in the longitudinal direction of each lamp IO is small at the center.

Since the end portions can be larger than the central portions, the illuminance distribution at the level where the object to be processed is located in the irradiation space l is uniform at least in the length direction of the lamp 10, or is uniform at the end portions. It can be made larger by . On the other hand, by uniformly or appropriately setting the width S of the gap between adjacent lamps 10, the illuminance distribution in the direction in which the lamps 10 are arranged side by side can be made uniform. Since the lamps 101, 102 and the lamps 108, 104 are disposed so as to be displaced to approach the level P where the object to be processed is located, the peripheral edge of the object to be processed in the direction in which the lamps 10 are arranged is in the center. In comparison, the object is heated with a large irradiation energy, which offsets the temperature drop due to heat dissipation at the peripheral edge, and eventually the entire surface of the object to be processed is heated at a uniform temperature. For example, when the workpiece is a relatively large semiconductor wafer with a diameter of 5 inches made of single-crystal silicon, etc., in a conventional irradiation heating furnace, the heating temperature may be uneven at the periphery of the wafer. It is possible to reliably prevent damage such as the "slip line" that occurs.

Note that the ramp, which is moved to approach the level at which the object to be processed is positioned, should be placed only at the end where there is a risk of low temperature and the occurrence of "s" line, so it is not necessary to place it at both ends. It may be placed at one end.

By the way, in the above embodiment, each lamp IO
The air from the blower 5 flows along the length direction of the enclosure 11 from one end located near the outlet of the second air duct member 4, and the air flows through the other end located near the entrance of the second air duct member 60. The wind from the exhaust fan 7 flowing along the length of the body 11 forcibly cools the entire length of the envelope 11, and at the same time, the main mirrors 2 and 8 are also forcibly cooled over their entire length. Therefore, by setting the air volume of the blower 5 and the exhaust fan 7 to be the same or similar to each other, the envelope 1
1 and the main mirrors 2 and 8 can be cooled in a good and stable manner at all times without causing large fluctuations in the cooling state of the main mirrors 2 and 8. Also.

The sealing part 12.12 of the lamp 10 is connected to the side mirrors 20 and z1.
The lamp IO is located outside of the filament 16 so that it is not exposed to direct light from other lamps. Side mirror zO with mechanism and 21.
and the lamp supports 8 and 9 that cooperate with this prevent heat conduction from the central part of the sealing body 11 of the lamp 10, and that the sealing parts 12 and 12 are The lamp 10 is effectively cooled because it is exposed and located inside the air passage member 4 and the second air passage member 6.
Deterioration in the sealing portion 12.12 is significantly suppressed.

Therefore, even if the lamps 1o have a high output, or even if the adjacent lamps 1o are arranged in high density with a small distance apart, the envelopes 11 and sealing parts 12, 12 of the lamps 1o are High temperatures are prevented and the service life of these lamps 10 is not shortened.

Here, an example of the temperature increase test in the above example is given.
The heating temperature change when the rated power of 1,600 W was supplied to each lamp IO was measured by bonding thermocouples at several locations in the center and periphery of a 4-inch square silicon wafer with a thickness of 450 ym. However, as shown in Figure 5, the measured temperature change at the center reached a high temperature of 1400°C by the time 10 seconds had passed after lamp 100 was turned on, and the measured temperature change at the periphery also reached the center shown in Figure 5. It was confirmed that the peripheral area was heated in the same way as the central area, which was almost the same as the measured temperature change in the central area.

Furthermore, when the rated power of 8ZOOW is supplied, the temperature reaches 1400℃ within 8 seconds after the lamp is turned on.

In either case, the entire surface layer of the silicon wafer was finally melted in a short period of time. in this way.

It is extremely important in the semiconductor manufacturing process that a temperature high enough to melt a silicon wafer can be obtained in an extremely short period of time, and that the entire surface can be heated at a uniform temperature.

It becomes possible to achieve a large area, short time heating, and uniform heating temperature, which was impossible with conventional irradiation heating furnaces.

Adding the same and other effects, each of the lamps 1o has the following effects:
Instead of the conventional method of providing a cap at both end sealing parts and supporting the lamp through the cap, it is possible to support the lamp through the outer wall surface of the tubular part in the vicinity of the both end sealing parts 12.12 of the enclosure 11. Since the lamp supports 8 and 9 support the lamps, the sealing portions 12, ]2 can be exposed in a bare state, and therefore the heat dissipation of the sealing portions 12, 12 is extremely effective. This prevents the electrically conductive members 18, 18 sealed within the sealing parts 12, 12 from being oxidized and disconnected, so that the service life of the lamp is not shortened.

This effect can be reliably and significantly obtained by positioning the sealing portions IZ, 12 within the cooling air path. Since the lamp supports 8 and 9 that support the lamp 10 are fixed to the water-cooled side mirrors 20 and 21,
They can be indirectly cooled by heat conduction, and adverse effects such as deformation due to the heat of the lamp 10 can be prevented. Supporting the lamp lO in its tube-shaped portion in this manner means that the supported tube wall portion is the coldest point inside the envelope, and in the case of a haloke 9 lamp, the temperature of the coldest point is lower than that of the halogen. The temperature must be 120°C or higher, which is necessary to maintain the cycle, but in high-output halogen lamps, the temperature at the coldest point must be 120°C or lower (15) h7x<, tjt The halogen cycle is not inhibited. In addition, in the heat treatment of semiconductors in an irradiation furnace, if Lanzoro gold is provided, dust generated from the adhesive layer etc. will have a serious adverse effect on the characteristics of the semiconductor, but the sealing part lz.

Since 12 can remain naked, such a problem does not occur.

As described above, the irradiation heating furnace of the present invention comprises a plurality of lamps each comprising a long rod-shaped tubular enclosure and a filament having alternating non-light-emitting parts and light-emitting parts arranged along the tube axis of the enclosure. of the plurality of lamps are close to the mirror and their tube axes are parallel to each other;

The structure is characterized in that at least one of the lamps located on the end side is displaced so as to approach the level at which the workpiece to be heated by being irradiated with light is positioned, so that it can be used for a large area. It is possible to heat the workpiece in a short time, and it is also possible to heat the entire surface at a uniform temperature, preventing the occurrence of damage such as "slip lines", suitable for heat treatment.

[Brief explanation of drawings]

FIG. 1 is an explanatory sectional view showing one embodiment of the present invention. FIG. 2 is an explanatory sectional view of the lamp and mirror in FIG. 1 viewed from the side, FIG. 8 is an explanatory diagram of support for the lamp, and FIG. 4 is an explanatory diagram of the lamp used in the present invention. FIG. 5 is a characteristic curve diagram regarding heating temperature changes in a specific device of the irradiation heating furnace of the present invention. ■-Irradiation space 2.8 Main mirror 4 First air path member 5 Air blower 6 Second air path member 7 Air exhaust device 8.9 Lamp support

Claims (1)

[Claims] 1) A plurality of lamps each having a filament provided with alternating non-light-emitting parts and light-emitting parts in a long rod-shaped tubular envelope along the tube axis of the envelope are arranged close to a mirror and each other's tubes are The axes are parallel to each other, and at least one of the plurality of lamps located on the end side is displaced so as to approach a level at which a workpiece to be heated by being irradiated with light is positioned. An irradiation heating furnace characterized by: